Process for manufacturing wheels and pulleys



' Sept. 29, 1925.

jx PROCESS FOR `IIANUFACTURING WHEELS AND PULLIYS Filed Feb. 28. 1925 Patented Sept. 29, 1925.

UNITED STATES LEON STENZ, OF WURZBERG, GERMANY.

PROCESS FOR MANUFACTURING WHEELS ANDv PULLFYS.

f Application filed February 28, 1925. Serial No. 12,402;

To all whom t may concern.'

Be it known that I, LEON STENZ, a German subject, residing at Wurzberg, Germany, have invented certain new and useful Improvements in Processes for Manufacturing W'heels and Pulleys, of which the following is a specification.

This invention relates to a cold process for manufacturing wheels and pulleys having rims, and if desired, bosses from flat blanks cut from a sheet of metal of suitable thickness.

Rail wheels with flanged rims have been made by cutting out a groove, by means of a saw or suitable tool, on the circumference of a circular blank and then forming the rim in the hot state by means of a rolling or spinning action. It has also been proposed in this hot process to split the rim by means of a cutting operation which leaves the rim with an incision of V form, whereupon the legs of the V are rolled or spun in the hot state to the desired form for the wheel. In both these methods the material must necessarily be worked in the hot state.

The object of the present invention is to form wheels and pulleys of all kinds from fiat blanks by means of a cold process and without danger of weakening the wheel in any part.

According to this invention the known method of splitting the edge to be formed into a rim or boss is employed, whereby the blank has imparted to it a V-formed incision with the legs of the V projecting out from the plane of the blank. When turning over the legs of the V bythe cold process, the danger arises of causing the metal to flow from the root of the V, and in this way a thin or weakened portion of the wheel results at the point where the rim or iiange leaves the central web or plate. This weakening may even amount to a rupture of the metal at this point. According to this invention such defects are avoided by introducing a staving action simultaneously with the forming or metal spinning action, and the direction of the flow of the metal in this staving action is towards the root of the V. This result is obtained by holding the blank between the halves of a rotatable die chuck, shaped out to the external shape of the wheel or pulley, and the blank is held in this die chuck during the processes of splitting to form the V-shaped incision and the rolling or metal spinning process which forms the rim, flange or boss. During the process of splitting, the legs of the V split are forced apart or spread so that they touch or almost rest on the lateral surfaces of the hollowed out part of the die corresponding to the outer shape of the wheel. When now the forming roll is pressed into the V-shaped incision, the outer parts are first acted upon, and the shaping and How of metal takes place towards the root of the V. Throughout this process, the internal formed surfaces of the chuck constitute an anvil or counterpressure surface which prevents further spreading or stretching of the metal at the root of the V and thereby increase the staving action arising from the frictional resistance offered to the forward feeding of the form roll.

The invention will be understood from the following description of the method which I may adopt for forming the rim on a pulley by my improved cold process, reference being made to the accompanying drawings in which:

Figure l is a section of a suitable blank from which a wheel or pulley may be formed in accordance with this invention.

Figure 2 is a section of a wheel such as may be formed in accordance with this invention.

Figure 3 is a sectional diagram, showing the blank inserted in the chuck die and after the process of splitting has been completed.

Figure 4l is a diagram illustrating the commencement of the process of forming or metal spinning the rim into shape.

Figure 5 illustrates the completion of the forming process in the case of a rim having the sectional shape shown in Fig. 2.

Figure 6 illustrates a further shape of rim which may be derived from the rim formed as in Fig. 5.

Figure 7 illustrates a further derivation formed from the rim as illustrated in Fig. 6.

In carrying the invention into effect a blank a as shown in Fig. 1 is required to be formed by a cold process into a wheel having a rim as shown in Fig. 2. The blank is inserted in a two part chuck o, Y), which is shaped out to form a. die for the external shape of the wheel and is provided with pinsy or dogs b1 which engage in the openings formed in the blank, the additional holes b2 also ensuring the proper centering of the blank in the chuck and the rotation of the blank with the chuck. Aiwcircular rlotnat--IV` Y ing splitting tool of the contour illustrated at c, in Fig. 3,-is then applied in the known manner so as to split the edge of the blank to form a V-shaped incision, the legs of the V, being spread so that they practically lie on the outer rim of the die part of the chuck, whilst the point of the V is just short of the base of the hollowed out semi-circular sectioned part of the chuck, by an amount which is approximately equal to the desired thickness of the metal at this point.

After this operation is completed, the forming or spinning roller d indicated in Fig. 4 is inserted in the tool rest and pressed radially into the V-shaped split. In this operation the roller first works on the outer parts of the legs of the V, as can be seen in Fig. 4, so as to spread these legs still further and pin them against the outer internal surfaces of the die, that is to say against the parts of the hollowed out portion of the die most remote from the point a2. The rollerd thus works the metal from the circumference radially inwards towards the point a2 and in this working, the surface of the die forms an anvil or counter pressure surface. The counter pressure to the staving action is also supplied by the frictional grip which is exerted on the blank between the roller and the chuck. The effect of the actions described is to cause the metal to flow from the rim towards the root of the V-split and in the nished wheel there is consequently no weakness at the points a3, but rather a strengthening occurs at this point.

From the roller or pulley formed as shown in Fig. 5, a roller of the form shown in Fig. 6 may be derived by employing, after the half-round forming wheel, a second former. The parallel upstanding rims a4 of Fig. 6, may be turned in as shown in Fig. 7 at a5. These forms are merely shown to indicate the possibilities, whether the invention is applied to the rims or the bosses of wheels.

I claim:

Process for forming flanged wheels in the cold state from flat wheel blanks cut from sheet metal, consisting in holding the wheel blank between rotatable split dies with the edge to be flanged projecting, forming a V- shaped split in the projecting edge and spreading the legs ofthe V-split out to the approximate width of the flange, imparting a simultaneous staving and forming action to the legs of the V-split by feeding a forming tool with a half round contour between the legs of said split and in said feeding movement gripping the said legs between the forming tool and the internal surface of the die to pin the peripheral part of said legs and cause the metal to flow from the outer edges of the Vssplit towards the point of the saine.

LEON STENZ. 

